Graphing in Physics
Graphing
• A way to display data that is collected in an experiment.
• They must be constructed accurately so data is understood.
• Three main types of graphs: line, pie and bar.
4 parts of a graph
1. Title & Axis labels
2. Independent variable
3. Dependent variable
4. Scales for variable
Parts of the Graph
Title- Depicts what the graph is about. It should be a statement placed above the
graph to help explain the graph. Axis labels give units and description of data.
The Independent Variable- it is the ONE thing in the experiment that is controlled by the experimenter. It usually concerns time, depth, or temperature. It is on the horizontal or x-axis.
Parts of a Graph
• Dependent Variable –is the variable that is directly affected by the changes in the independent variable. This variable is placed on the vertical or Y-axis.
• Scales for each variable- In order to plot a graph you must set a scale to include all the data points. The scale will start with 0 and climb in equal intervals such as 2,5,10 etc. The scales for the x and y axis can be different.
Graphing Scientific Data
• Use the best fit line. You don’t connect dot-to-dot but draw a line that goes through most of the points.
• Interpolation- is used when you get approximate values that are between points.
• Extrapolation- is used to approximate values beyond the range of the data.
Accuracy & Neatness in graphing
• To convey the data correctly all parts of the graph must be accurate and neat.
• Rulers and graph paper should always be used.
• Graphs must fit the graph paper you can adjust the scale so they fit.
• A graph is incomplete if the title and axis labels are missing.